Instrument for firing pin inspection



Feb, 8, 1944. L. MEISTER INSTRUMENT FOR FIRING PIN INSPECTION Filed Dec.1, 1942 .M ii.li-L

Elma/14m i-sier Lem ME Patented Feb. 8, 1944 UNITED STATES PATENT OFFICE(Granted under the act of March 3, 1883, as I amended April 30, 1928;370 0. G. 757) The invention described herein may be manufactured andused by or for the Government for governmental purposes, without thepayment to me of any royalty thereon.

This invention relates to apparatus for inspecting and testing firingpins in the course of their production preparatory to being placed inthe explosive shell or projectile, and more particularly, to the type offiring pin provided with a collar. The object of this invention is todevise apparatus for inspecting firing pins of the type described, moreparticularly, to inspect such pins with reference to the dimensionbetween the conical point of the pin and the underside surface of itscollar. It is of prime importance to the satisfactory performance of thefiring pin that this dimension be maintained within close tolerance ofstandard. A further object of this invention is to provide an inspectionapparatus of the character described which will be capable of highaccuracy, simple to manipulate, of large productive capacity, andadapted to be readily adjusted to accommodate different kinds and sizesof firing pins.

For the attainment of these and such other objects of inventions as mayherein appear or be pointed out, I have shown one embodiment of myinvention in the accompanying drawing, wherein:

Fig. 1 is a side, sectional elevation of the machine.

Fig. 2 is a plan view thereof.

Fig. 3 is a partial sectional view taken on the line 3-3 of Fig. 2, and

Fig. 4 is an isometric View of the finger block of the rejecting manual.

The top surface In of the apparatus is provided with a long groovedpassage H extending along the length thereof of sufficient width toaccommodate the collar 2 of firing pins I and provided along its bottomwith a long slotted passage l2; both the groove l l and slot [2 are openat both ends of apparatus table I 0, so that the firing pins may beinserted at one end (the end lowermost on the sheet, Fig. 2) andremoved, at least, the ones passing inspection, at the other end (theend uppermost on the sheet, Fig. 2). Fresh pins, inserted as described,are moved along the grooved (H) slot l2 to be singly received in arejecting manual 20, more particularly, in the finger 2i thereof.Rejecting finger or block 2| is secured to one end of a rod 22, theother end of which extends through the front wall I3 of the machinewhere it terminates in a knob 23. A collar 24 is fastened on rod 22;compression spring 25 interposed between collar 24 and machine wall l3normally maintains finger block 2i in its rightmost position (as viewedin Figs. 1 and 2).

Finger block 2| is provided with a ledge 26 which is fiush with the topsurface of the slotted (12) bottom of groove H. In the rightmost, normalposition of finger block 2!, its ledge 26 is spaced from the oppositeside of slot 12 a distance equal to the width of the slotted passage I2.Hence in the normal, right most position of rejector manual 20,particularly, its finger ledge 26, the ledge will provide a surface tosupport the collar 2 of firing pins l as they are moved up (as viewed inFig. 2) to the rejector manual. For the purpose of aligning the singlepins precisely on the center line of the rejector manual (rod 23) andfor holding the pin thereat, the finger ledge 26 is provided with aV-shaped notch 21, see Fig, 4. The compression spring 25 together withnotch 27 cooperate as a detent to accurately position the individual pinas it is moved to the rejector manual 2t.

A firing pin, properly positioned at, and held by, the rejector manual2% as shown in Fig. 1, has its conical (lower) point substantially inthe center line AA of an optical system now to be described. Anincandescent lamp 3! and condenser lenses 32 are contained in acollimating tube at, the centers of the lamp, condenser and tube beingsubstantially on the said optical center line A-A. Collimating tube 30is supported, preferably by the adjustable pivot connection I 4, at theupper end of a standard I5 resting on the floor is of the machine for anextent of sliding movement. Rod I'l, screwed into standard l5, may beturned, as by its knob It at the front of the machine, to adjust theposition of the collimating tube relative to the suspended pin I, Fig.1.

Light from the collimating tube 36 is directed to flood the suspendedpin (i) held in position at the rejector manual, and to pass through a.lens tube 33 containing one or more enlarging lenses. As clearly shownin Fig. 1, lens tube 33 is suspended as by means of a pivot connectionHi from the top surface ill of the apparatus. The enlarged image orshadow of the firing pin under inspection, emerging from lens tube 33,is directed to mirror or reflecting surface 34, from which it isreflected onto ground glass screen 35 set in the front panel of theapparatus. Reflector 34 is mounted, as by a pivot connection, Fig. 1,for adjustment to reflect the enlarged pin shadow upon the ground glass35.

The enlarged shadow of a firing pin held at (and by) rejector manual 20,is observed in ground glass 38, to determine whether the aforementioneddimension between its conical point and its collar 2 is accurate withinthe prescribed tolerances. To make this determination precisely, a gauge40 (see especially Fig. 2) is pivotally mounted, as by wing screw 4|, onground glass 35. Gauge 40 is made adjustable to accommodate differentlengths or types of firing pins.

If the enlarged pin shadow on the ground glass screen is of the properheight (as determined by gauge 40) the pin under observation iscontinued along the slotted passage [2 to emerge from the uppermost end(as viewed in the sheet, Fig. 2) of the slotted passage for deposit in abox or container 5 reserved for pins which had passed the inspectiontest. If the pin shadow is above or below the gauge 40, rejector manual20 is pulled outwardly, to withdraw ledge 26 from underlying relation topin collar 2, thus causing the rejected pin to fall through slot II fordeposit in discard or reject box 8.

In the operation of the apparatus, the operator uses both hands, onehand for pushing the fresh firing pins to the rejector manual 20 and forpushing the good pins beyond the rejector manual and into the collectingbox 5; the other hand is held on the knob 23 of the rejector manualready to pull out the manual whenever an unsatisfactory pin isencountered, to drop the pin into discard box 6. The firing pins may beconveniently and rapidly assembled in the grooved passage III by beingplaced on the sloped top surface ill, see Fig. 1, and permitted to rolldown to seat themselves in the grooved passage.

I claim:

1. In apparatus for inspecting firing pins of the type provided with acollar with reference to the dimension between its point and the uniderside of its collar, a table surface provided with a passagesufilciently wide for the pins to clear and grooved to accommodate theircollars, the said grooved passage being open at both ends of the saidtable for receiving fresh pins at one end and for removing approved pinsat the other end, a recess in one side of the said grooved passage andenlarged at one point sufiiciently wide for the firing pin collar todrop through, a block disposed in the said recess and rabbetted toconform to the said groove and to present a ledge spaced from theopposite edge of the said passage a suflicient distance for pinclearance, a rod extending from the said block to an accessible point atthe front of the: apparatus and terminating in a knob, spring meansurging the said block rearwardly to position its ledge in supportingrelation to the pin collars, whereby in the normal position of the saidblock the firing pins in being moved along the said grooved passage willpass the enlarged point, a V-notch provided in the said block ledge forcentering the pins, an optical system including a light source, anenlarging objective, a condenser for collimating light beams past thesuspended point of a firing pin held at the said enlarged point of thegrooved passage into the said objective, a reflecting surface positionedin said light beam and a ground glass screen to receive an enlargedimage of the said block according to the inspected dimension as shown bythe said gauge.

2. In apparatus for inspecting firing pins of the typ provided with acollar with reference to the dimension between its point and theunderside of its collar, a table surface provided with a passagesufiiciently wide for the pins to clear and grooved to accommodate theircollars, the said grooved passage being open at both ends of the saidtable for receiving fresh pins at one end and for removing approved pinsat the other end, a recess in one side of the said grooved passage andenlarged at one point sumciently wide for the firing pin collar to dropthrough, a block disposed in the said recess and rabbetted to conform tothe said groove and to present a ledge spaced from the opposite edge ofthe said passage a sufficient distance for pin clearance, a rodextending from the said block to an accessible point at the front of theapparatus and terminating in a knob, spring means urging the said blockrearwardly to position its ledge in supporting relation to the pincollars, whereby in the normal position of the said block the firingpins in being moved along the said grooved passage will pass theenlarged point, an optical system including a light source, an enlargingobjective, a condenser for collimating light beams past the suspendedpoint of a firing pin held at the said enlarged point of the passageinto the said objective, a reflecting surface positioned in said lightbeam and a ground glass screen to receive an enlarged image of the pin,and a gauge associated with the said screen for measuring the saidinspected dimension on the enlarged image.

3. In apparatus for inspecting firing pins of the type provided with acollar with reference to the dimension between its point and theunderside of its collar, a table surface provided with a passagesufficiently wide for the pins to clear but not for their collars, thesaid passage being open at both ends of the said table for receivingfresh pins at one end and for removing approved pins at the other end, arecess in one side of the said passage and enlarged at one pointsufiiciently wide for the firing pin collar to drop through, a blockdisposed in the said recess and normally spaced from the opposite edgeof the said passage a sufllcient distance for pin clearance, a rodextending from the said block to an accessible point at the front of theapparatus and terminating in a knob, spring means urging the said blockrearwardly tu position its ledge in supporting relation to the pincollars, whereby in the normal position of the said block the firingpins in being moved along the said passage will pass the enlarged point,an optical system including a light source, an enlarging objective, acondenser for collimating light beams past the suspended point of afiring P held at the said enlarged point of the passage into the saidobjective, 9, reflecting surface positioned in said light beam and aground glass screen to receive an enlarged image of the pin. a gaugeassociated with the said screen for measuring the said inspecteddimension on the enlarged image, and a box underlying the said passageat its said enlarged point for receiving disapproved pins fallingthrough the said enlargement upon pulling the knob of the said blockaccording to the inspected dimension as shown by the said gauge.

4. In apparatus for inspecting firing pins of the type provided with acollar with reference to the dimension between its point and theunderside oi its collar, a table surface provided with a passagesufllciently wide for the pins to clear but not for their collars, thesaid passage being open at both ends of the said table for receivingtresh pins at one end and for removing approved pins at the other end, arecess in one side 01 the said passage and enlarged at one pointsufliciently wide for the firing pin collar to drop through, a slidableblock disposed in the said recess and normally spaced from the oppositeedge of the said passage a sufilcient distance for pin clearance,whereby in the normal position or the said block the firing pins inbeing moved along the said passage will pass the enlarged polnt meansfor retracting said block, on optical system including a light'source,an enlarging obiective, a condenser for collimating light beams past thesuspended point ota firing pin held at the said enlarged point or thepassage into the said objective, and a ground glas screen to receive anenlarged image of the pin, a gauge associated with the said screen formeasuring the said inspected dimension on the enlarged image, a, boxunderlying the said grooved passage at its said enlarged point forreceiving disapproved pins, and manual means for withdrawing the saidblock to the type provided with a collar with reference to the dimensionbetween its point and the underside of its collar, a table surfaceprovided with a passage sufilciently wide for the pins to clear, thesaid passage being open at both ends of the said table for receivingfresh pins at one end and for removing approved pins at the other end, arecess in one side of the said passage and enlarged at one pointsufficiently wide for the firing pin collar to drop through, a slidableblock disposed in the said recess and normally spaced from the oppositeedge or the said passage a sufiicient distance for pin clearance,whereby in the normal position or the said block the firing pins inbeing moved along the said passage willpass the enlarged point, meansfor retracting said block, an

optical system including a screen; tor-collimating light beams past thesuspended point of a firing Din held at the said recessed point of t e"LEO MEIS'I'ER.

